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' J'. H. TOPPER. PROCESS OF PREPARING WOODEN TABLETS WITH BLAGKBOARP SURFACES.

' No. 548,676. Patented 00t.29,1895.v

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UNITEDSTATEs PATENT'FFICEOA JOSEPH H. TOPPER, OF UNION CITY, PENNSYLVANIA, ASSIGNOR OF ONE- HALF TO JOHN J. BRADY, OF SAME PLACE.

PROCESS OF PREPARING WOODEN TABLETS WITH BLACKBOARD SURFACES.

' SPECIFICATION forming part of Letters Patent No. 548,676, dated October 29, 1895. Application filed February 25, 1895. Serial No. 539,713. (No specimens.)

To to whom it may concern:

Be it known that I, JOSEPH 11. TOPPER, of Union City, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Processes of Preparing Wooden Tablets with Blackboard Surfaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same.

My invention relates to a process of preparing a wooden tablet with .a blackboard surface upon which can be written with a slatepencil and from which the written matter can be readily washed-or erased without injuring the tablet.

With this object in view my invention consists in the process of preparing the surfaces of said tablet hereinafter described, and pointed out in the claim.

In the accompanying drawings, Figure l is a plan of a wooden tablet provided with my improved means for preventing warping and splitting of the tablet without interfering with the expansion and contraction of the wood in the direction of its grain. Fig. 2 is a section on any of lines 2 2, Fig. 1.

Referring to the drawings, A designates a wooden tablet composed of a single board .having the grain of the Wood running longitudin ally thereof. The board at its edges that extend transversely of the grain of wood is provided with a sheet metallic binding B. This binding is secured to the tablet by having it overlap the sides of the tablet and then pressing the overlapping portions of the binding tightly against the sides of the tablet. The binding,however, does not hug the overlapped edges of the tablet; but the binding is so applied as to leave an air-space O between the overlapped edges and the binding.

By the construction just described splitting and warping of the board are prevented without interfering with the expansion and contraction of the Wood in the direction of its grain, any expansion of the wood being accommodated by the spaces provided between the sheet metallic binding and overlapped edges of the tablet. The binding is preferably extended around the corners of the tablet,

lampblack, and emery-dust.

as shown, to avoid any splitting of the tablet at or near the longitudinal edges thereof.

Having thus described my improved construction for preventing splitting and warping of a Wooden tablet without interfering with the expansion and contraction of the wood in the direction of its grain, I will proceed with a description of the preparation of the surfaces of the tablet so that any matter written thereon by meansof a slate-pencil can be readily erased Without injuring the tablet. I first coat said surfaces with a liquid composition of Japan drier, benzine, lampblack, and emery-dust. For one gallon of this liquid I prefer to mix three quarts of Japan drier with one quart of benzine, and then add one pound of lampblack and one pint of emerydust and mix the same with the drier and benzine, and when the ingredients have been thoroughly mixed the compound is applied to the surface of the tablet by means of a brush.

Having applied a coat of liquid composed of Japan drier, benzine, lam pblack, and emerydust, asjust described, and permitted said coat to dry, I next apply a coat of liquid composed of shellac, potash dissolved in boiling water, For one gallon of this compound I prefer to use one and oneeighth pounds of shellac, two ounces of potash dissolved in one gallon of boiling water, one quarter pound of lanlpblack, and one quart of emery-dust, the ingredients being suitably mixed and the compound being applied to the surface of the tablet by means of a brush.

I-Iaving applied the second coat to the tablet and permitted saidcoat to dry, I next apply a coat composed of shellac, wood-alcohol, lampblack, and emery-dust. For one gallon of this compound I prefer to use one pound of lampblack, one pint of emery-dust, and the remainder of shellac and Wood-alcohol in equal parts, the shellac being thoroughly cut by and mixed with the wood-alcohol before adding the lampblack and emery-dust and the compound being applied to the tablet by means of a brush.

The preparation of the surfaces of the wooden tablet therefore consists, first, in applying to said surfaces a coat of liquid composed of Japan drier, benzine,1ampblack, and emery-dust, suitably compounded in suitable coat of liquid consisting of suitable proportions of shellac, potash dissolved in boiling water, lamp-black and emery-dust, and permitting said second coat to dry, and, thirdly, applying to the twice-coated surfaces a coat of liquid consisting of suitable proportions of shellac, wood-alcohol, lamp-black and emery dust, substantially as set forth.

In testimony whereof I sign this specification, in the presence of two witnesses, this 15th day of December, 1894.

JOSEPH H. TOPPER.

Witnesses:

A. J. TERRILL, JOSEPH TOPPER, Sr. 

